Dual‐Defects Adjusted Crystal‐Field Splitting of LaCo_1−xNi_xO_3−δHollow Multishelled Structures for Efficient Oxygen Evolution

Abstract

To boost the performance for various applications, a rational bottom‐up design on materials is necessary. The defect engineering on nanoparticle at the atomic level can efficiently tune the electronic behavior, which offers great opportunities in enhancing the catalytic performance. In this paper, we optimized the surface oxygen vacancy concentration and created the lattice distortion in rare‐earth‐based perovskite oxide through gradient replacement of the B site with valence alternated element. The dual defects make the electron spin state transit from low spin state to high spin state, thus decreasing the charge transport resistance. Furthermore, assembly the modified nanoparticle subunits into the micro‐sized hollow multishelled structures can provide porous shells, abundant interior space and effective contact, which enables an enhanced mass transfer and a shorter charge transport path. As a result, the systemic design in the electronic and nano‐micro structures for catalyst has brought an excellent oxygen evolution performance.

Constructed Interfacial Oxygen‐Bridge Chemical Bonding in Core‐Shell Transition Metal Phosphides/Carbon Hybrid Boosting Oxygen Evolution Reaction

“…A highly efficient Fe−N−C ORR electrocatalyst has been designed [40] . The hollow structure can enhance the chemical diffusion, decrease the charge transport path, and also provide more efficient surface area for catalysis [41] . Nanocomposites for CoP/carbon materials should be rationally designed structures towards high OER efficiency, and the detailed mechanism of the synergistic effect between the components should be well‐explored.…”

Activation Strategies of Perovskite‐Type Structure for Applications in Oxygen‐Related Electrocatalysts

“…Perovskite‐type oxide nanostructures with novel morphological characteristics can be obtained by making full use of existing synthetic techniques. [ 34–36,124–126 ] For example, the La 0.8 Sr 0.2 Co 0.2 Fe 0.8 O 3 (LSCF) morphological control is achieved via adjusting the percentage of nitrate weight in the precursor solution, and studied the effect of morphology for OER electrocatalysis activity in alkaline media. [ 124 ] Compared with the nanorods (LSCF‐20%) and nanoparticles (LSCF‐30%) catalysts, 1D nanofibers (LSCF‐10%) exhibit excellent OER catalytic activity and stability in alkaline solution.…”

“…assembled the modified nanoparticle subunits into microsized hollow multishell structures (Figure 7g–l). [ 126 ] The TEM images show that LaCo 0.5 Ni 0.5 O 3– δ had spherical morphology with triple shells. Meanwhile, the elemental mappings reveal that the La, Co, Ni, and O elements are homogeneously distributed in the entire LaCo 0.5 Ni 0.5 O 3– δ spheres.…”

“…Reproduced with permission. [ 126 ] Copyright 2020, Wiley‐VCH.…”

Small Structures Bring Big Things: Performance Control of Hollow Multishelled Structures

“…In the past decade, HoMSs have been widely adopted in diverse catalytic reactions, such as photocatalysis, [ 114–123 ] electrocatalysis, [ 124–130 ] gas sensors, [ 33 ] and other catalytic fields. [ 131–138 ] The hierarchical assembly of multiple shells within HoMSs can fully expose their volumetric effective surface for catalytic reactions.…”